WASHINGTON — In the early months of 2014, a group of about 30 corporate lawyers, coal lobbyists and Republican political strategists began meeting regularly in the headquarters of the U.S. Chamber of Commerce, often, according to some of the participants, in a conference room overlooking the White House. Their task was to start devising a legal strategy for dismantling the climate change regulations they feared were coming from President Obama.

The group — headed in part by Roger R. Martella Jr., a top environmental official in the George W. Bush administration, and Peter Glaser, a prominent Washington lobbyist — was getting an early start.

By the time Mr. Obama announced the regulations at the White House on Monday, the small group that had begun its work at the Chamber of Commerce had expanded into a vast network of lawyers and lobbyists ranging from state capitols to Capitol Hill, aided by Republican governors and congressional leaders. And their plan was to challenge Mr. Obama at every opportunity and take the fight against what, if enacted, would be one of his signature accomplishments to the Supreme Court.

Within minutes of the announcement, West Virginia’s attorney general, Patrick Morrisey, stepped before a bank of cameras for a news conference at the Greenbrier resort in his home state. Flanked by Mike Duncan, the president of the American Coalition for Clean Coal Electricity, one of the nation’s top coal lobbying groups, and Greg Zoeller, the attorney general of Indiana, Mr. Morrisey announced that a group of at least 15 Republican state attorneys general were preparing to jointly file a legal challenge to Mr. Obama’s proposal.

“The final rule announced Monday blatantly disregards the rule of law and will severely harm West Virginia and the U.S. economy,” Mr. Morrisey said. “This rule represents the most far-reaching energy regulation in this nation’s history, drawn up by radical bureaucrats and based on an obscure, rarely used provision of the Clean Air Act.”

“Our coalition, in short order, will comprise of many states, consumers, mine workers, coal operators, utilities and businesses who are united in opposition to this radical and illegal policy,” he added.

While Mr. Obama had not even put forth a draft proposal of his plans when the group started its work, the president had made plain in several speeches that he intended to act forcefully on climate change — and that he would flex the muscle of his executive authority to do so. “If Congress won’t act soon to protect future generations, I will,” he said in his 2013 State of the Union address. The lawyers and lobbyists wanted to be ready to fire back hard and fast when he did.

In devising its strategy, the group worked closely with the office of Senator Mitch McConnell of Kentucky, the majority leader whose coal-producing home state also stands to suffer under the regulation. While Mr. McConnell opposes the climate change regulations, his advisers knew that he had little chance of enacting legislation to block them in Congress. Instead, Mr. McConnell has taken the unusual step of reaching out directly to governors and attorneys general, urging them to refuse to submit compliance plans for the regulations, and encouraging a state-by-state rejection of the rules.

Mr. Morrisey, whose coal-producing home state is also struggling with the nation’s highest unemployment rate, was chosen as the public face of the suit. But key strategists joining the original planning were Gov. Greg Abbott of Texas, a former attorney general there, and Scott Pruitt, the attorney general of Oklahoma. Both already had experience suing the Obama administration over major Clean Air Act regulations.

An important ally in the effort was the American Legislative Exchange Council, or ALEC, a conservative advocacy group that pushes policy through state legislatures. Typically, the council’s committees of corporate members will craft a model bill designed to push through policies it supports, such as rolling back environmental regulations.

At a July meeting in San Diego, ALEC’s energy committee — which includes Mr. Duncan, the coal lobbyist who also worked closely with Mr. McConnell on his tactics — enacted a model bill designed to directly support state attorneys general who legally challenge the climate change plan. According to a person present at that July meeting, the bill would allow states to create funds, which could be funded by corporate donations, to support legal challenges to the climate change rules.

While it is not unusual for major corporations to sue the federal government over environmental regulations, people involved in the effort to craft a legal strategy against the climate change rules said the time, labor and coordination of the effort were unusual. That effort reflects the sweeping scope of climate change regulations, which, unless struck down in the Supreme Court, could transform huge sectors of the economy, potentially crippling the coal industry and other industrial sectors whose economic well-being relies on coal.

The Obama administration contends that despite the massive scale of the challenges trained against it, the climate change plan is legally sound. “The final rule is built on a rock-solid legal foundation,” said Thomas Reynolds, a spokesman for the agency.

“E.P.A. is using its clear authority under the Clean Air Act to set emission standards for air pollutants,” he said. “The rule is wholly consistent with the law, and we are confident it will withstand any and all legal challenges.”

But Michael McKenna, a Republican energy lobbyist who has worked closely with the group, says that the attorneys general will not back down. “This rule was more aggressive than any of us could have imagined,” he said. “There is no lack of state attorneys general who would like to put a bullet in this thing.” The rules, a final, stricter version of a plan that the Environmental Protection Agency announced in 2012 and 2014, assigns each state a target for reducing its carbon pollution from power plants. States will be allowed to create their own plans to meet the requirements and will have to submit initial versions of their plans by 2016 and final versions by 2018.

The most aggressive of the regulations requires that by 2030, the nation’s existing power plants must cut emissions by 32 percent from 2005 levels, which is an increase from the 30 percent target proposed in the draft regulation.

The president on Monday called the new rules a public health imperative and “the single most important step America has ever taken in the fight against global climate change.” He also sought to wrap the policy in the legitimacy of transcendental values, noting that Pope Francis issued an encyclical in June, calling action on the issue a “moral obligation.”

Even as Mr. Obama acknowledged the steep resistance from coal-producing states and industry critics, he said it was up to the United States to adopt tough standards so that other countries like China would feel compelled to take similar steps.

But Mr. McConnell made it clear he would do everything in his power to combat the rules, which he said the president had crafted because he was “tired of having to work with the Congress the people elected.”

“That’s why the administration is now trying to impose these deeply regressive regulations — regulations that may be illegal, that won’t meaningfully impact the global environment, and that are likely to harm middle- and lower-class Americans most — by executive fiat,” Mr. McConnell said. “It represents a triumph of blind ideology over sound policy and honest compassion,” he added.

Correction:

An article on Tuesday about groups who are challenging President Obama’s climate change regulations misspelled the surname of a prominent Washington lobbyist who has worked to devise one of the legal strategies. He is Peter Glaser, not Glazer.

A version of this article appears in print on , on Page A1 of the New York edition with the headline: Move to Fight Climate Plan Started Early. Order Reprints | Today’s Paper | Subscribe